Some vendors have become irked and have lost confidence in the chain since the stores’ new computer merchandising system failed last summer.

The snafu with the system has left Neiman — and its Bergdorf Goodman operation — unable to verify inventory, it has said.

Operating blind, Neiman has been putting pressure on its suppliers to determine when it should restock its stores and discount its merchandise, vendors complained in interviews with The Post.

Neiman, when caught by surprise with excess inventory, has asked some vendors to buy back some of their unsold goods — without the benefit of a system that gives the vendors accurate information, they said.

“The information they send us is inaccurate and the onus is on us to prove how much of our product they sold,” said one agitated vendor who did not want to be identified. “We lost sales in December because Neiman didn’t know it had sold out of our product.”

A second vendor, who also spoke on the condition on anonymity, said it has not received a sales report from Neiman in about five months.

Neiman traces its inventory and merchandising problems to last August, when it moved to upgrade its 40-year-old system.

“I know many of our clients are trying to get the data they got in the past [from Neiman] and its been much more difficult,” said Gary Wassner, chief executive of Hilldun Corp., a lender to the fashion industry. “They don’t know how well their products are doing.”

Ares and CPP declined to comment, but according to a source with knowledge of the situation, CPP has written down its $750 million investment in Neiman to zero and has a “team working on reorganizing” Neiman’s $4.9 billion in debt.